Individualization of Drug Therapy Mode in a Patient with Disseminated Form of GIST by Determining Active Metabolites of the Drug (Tyrosine Kinase Inhibitor) in Blood Plasma

Abstract

An own experience of effective treatment of a patient with a disseminated form of gastrointestinal stromal tumor (GIST) with a preparation from the group of tyrosine kinase inhibitors (imatinib) is presented.

Relevance. Therapy of gastrointestinal stromal tumors is still a complex problem of modern oncology. Since 2001, a breakthrough has occurred in the treatment of patients with GISTO due to the successful use of a targeted drug from the group of tyrosine kinase inhibitors — imatinib, which is effective in the first line of inoperable and / or metastatic GISTs, and is also used for the neoadjuvant, adjuvant therapy of localized GISTs. The lack of response to therapy and, consequently, the progression of the disease, may be associated with a decrease in the therapeutic concentration of imatinib in the blood plasma. Determining the concentration of active metabolites of imatinib in the serum allows timely identification of potential causes of insufficient response to therapy and individual correction of the dose of the drug.

Materials and methods. In order to determine the significance of the correlation between increasing / decreasing the dose of imatinib and achieving a therapeutic response, we used a laboratory method of high performance liquid chromatography to determine the concentration of imatinib in serum.

Conclusion. Determination of the reduced concentration of active metabolites of imatinib in the blood plasma by high performance liquid chromatography with the detection of tandem mass spectrometry in a patient with disseminated form of GIST allowed to correct the dose of the drug and achieve a positive effect.